Test identification Suppose you were asked to analyze each of the situations described below. (
NOTE: Do not do these problems!) For each, indicate which procedure you would use (pick the appropriate number from the list), the test statistic (
z or
t), and, if
t, the number of degrees of freedom. A procedure
may be used more than once.
a. A personal trainer would like to know if a newly designed bootcamp regimen will significantly build body mass index (BMI). In an effort to test this, the trainer recorded the BMI for 15 different clients prior to the bootcamp and after the bootcamp. The trainer assumes the BMI’s are approximately normal. Does the bootcamp regimen as advertised?
b. In a study to determine whether there is a difference between the average jail time black and white offenders of minor drug possession are sentenced to, the law students randomly selected 25 cases of each type that resulted in jail sentences during the previous year. A 90% confidence interval was created from the results.
c. A bank branch manager is interested in estimating the average wait time for customers in the teller line. The manager records the times for 40 randomly chosen customers. Estimate the wait time with a 95% confidence interval.
d. A New York City mayoral candidate wants to assess his constituent’s opinions on the controversial “Stop and Frisk” police tactics. A sample of voters from 2 boroughs (Queens and Brooklyn) is selected and asked if they approve of this policy. Do the approval rates vary from each other?
e. Is there more gun violence in the summer heat than the winter cold? We get records of the number of gunshot wounds in January and July in a random sample of 50 emergency rooms.
f. A board of directors of a local homeowner’s association union organization wishes to amend the bylaws. A sample of the residents revealed 310 of 430 were in favor of the amendment. Does the board of directors have the required 75% majority?
Quick Reply
